Novel polymer compositions and method



United States Patent "Ice iflffiii plication, Serial No. 591,706, filed November 3, 1966, 3,404,132 with a mercaptan or thiol compound or their salts or NQVEL POLYMER COMPOSITIONS mixtures thereof. These polyelectrolytes are derived from AND METHOD Ritchie A. Wessling, Midland, and Ray G. Zimmerman, I, Shepherd, Mich., assignors to The Dow Chemical Com- 0 monomeric sulfonium salts described therein and have recurring units of the structure pany, Midland, Mich, a corporation of Delaware G N0 Drawing. Filed Feb. 23, 1967, Ser. N0. 617,834 R 7 Claims. (Cl. 260-795) R R R R \GB/ l I s 10 .01- =011 -!H-CH- ABSTRACT OF THE DISCLOSURE I The polymer compositions are the reaction product of R R f R R g a water-soluble polyelectrolyte derived from a sulfonium (II) salt with a mercaptan or thiol compound or their salts or wherein R has the same meaning as its counterpart heremixtures thereof in a basic solution, useful as water-retofore mentioned in the general formula (I) for the polysist-ant, non-conducting protective coatings. rner composition, R and R" each represent an alkyl group containing from 1 to 4 carbon atoms and A is a counterion which can be derived from any low molecular weight acid so long as it does not precipitate polymer or react with This invention concerns novel polymer compositions.

More specifically, it concerns compositions comprising polymer in aqueous solution. Suitable low molecular novel thermoplastic polymers having recurring units of the weight acids from which the counterion A can be derived structure include both inorganic acids such as hydrohalic acids Y z R R R R R R l S l S @CEEJOH- @(JH-CHz- (EHCH it B a ft 1% b R 1% c wherein R represents hydrogen or the methyl group, Y which provide a halide ion, e.g., chloride or bromide ion, represents an alkyl group containing from 1 to 4 carbon and carbonic acid which provides a bicarbonate ion, and atoms, and Z represents an alkyl, aryl, or aralkyl group organic acids such as acetic, propionic, butyric, maleic, which is stable in strongly basic solution such that the citric, or oxalic acid. The ratio of the units comprising the merc-aptan or thiol compound from which it is derived polyelectrolyte structure in a random grouping is reprecan form a mercaptide ion, except that when theZ group sented by the integers f and g in which the ratio f:g is the same as the Y group, b equals zero. Suitable merranges up to about 3:1 or to the ratio corresponding to captans from which Z can be derived include substituted the point of incipient water insolubility. These polyelectroand unsubstituted alkyl, aryl, or aralkyl compounds or 40 lytes useful in the practice of the invention can either be their salts, as well as mixtures thereof. The mole perisolated or directly reacted from the solution in which centage of the structural units in the polymer molecule they were prepared. comprising the novel composition in a random grouping Mercaptans or thiol compounds suitable for use in the is represented by a, b, and c. The percentage of a can practice of the invention include alkyl, aryl, or aralkyl range from 0 to 75 or to the point where the polymer mercaptans or their salts as well as mixtures thereof, so composition remains both thermoplastic and soluble in long as they react with base in aqueous solution to form conventional organic solvents such as dioxane, tetrahymercaptide ions which in turn react with the sulfonium drofuran, chloroform, and orthodichlorobenzene. The sum ion. Included are both substituted and unsubstituted alkyl, of the percentages b and 0 can range from 25 to 100, b aryl, or aralkyl compounds or their salts such as l-butanefrom 0 to 66.7, and c from 25 to 100 percent. thiol, l-pentanethiol, 3-methyl-l-butanethiol, 2,2-dimethyl The compositions of this invention are useful in such propanethiol, l-hexanethiol, l-heptanethiol, l-octanethiol, applications as a molding resin, as a coating on metals l-nonanethiol, l-decanethiol, l-dodecanethiol, Htetradecbecause of the good adhesion thereto which coating can anethiol, l-octadecanethiol, cyclohexyl mercaptan, and be fluorescent if desired as well as an ultraviolet light the like. Also included are aliphatic dimercaptans such as barrier, and as a wire coating because of good insulating 1,2-ethanedithiol, 1,3 propanedithiol, 1,4 butanedithiol, (non-conducting) properties. In addition, the compositions 1,5-pentanedithiol, 1,8-octanedithiol, and the like. can be cured at high temperature to become an infusible, In addition there are included aryl mercaptans or thiol insoluble, thermoset-like composition. The polymer comcompounds such as benzenethiol '(thiophenol), p-m'ercappositions of the invention are sufiiciently fusible to be totoluene, o-mefcaptotoluene, p't-butylbenzenethiol, shaped or molded by conventional techniques. methyl-4-t-butyl=benzenethiol, 2-naphthalenethiol, p-dimer- It is a primary object of this invention to provide captobenzene, o-dimercaptobenzene and the like. thermoplastic polymer compositions containing alpha-sub- Also included are aralkyl mercaptans such as a-merstituted xylylene units which can be prepared into coatcaptot lllene (benzyl mercaptan), a, x' dimercapto-pings, films, foams, resins, and powders, and yet can be Xylene and the like. converted into infusible, insoluble, thermoset-like prod- Solutions of the mercaptans or thiol compounds in an ucts. It is a further object to provide a method for preinert water-miscible organic solvent such as alcohol or paring the above compositions. dioxane can be employed and are usually preferred, but

In accordance with this invention it has been disare not necessary. covered that a novel polymer composition having recur- The P y formed y reaction h monofunctional ring units and properties of the type described above can mercaptans are soluble in organic solvents such as benbe prepared by reacting in a basic solution, water-soluble zene, dioxane, chloroform, and the like, if the a/(b+c) polyelectrolytes such as those described in copending apratio is not too large. The specific solubility characterissuitable solvent and cast into films or coatings. These coatings are insensitive to moisture, opaque to ultraviolet light, have good thermal and oxidative stability and good abrasion resistance. They adhere well to most substrates, particularly wood or metals, making them useful as coatings.

The softening points and molding temperatures of the new polymer compositions are related to the flexibility of the side groups Y and Z. Polymers with rigid groups such as benzyl and naphthyl soften above 50 C., while polymers with alkyl side groups such as tetradecyl soften at room temperature if the a/(b+c) ratio is not too large.

The novel thermoplastic polymer compositions of the invention can be thermally cured to produce hard, insoluble, infusible, thermoset-like materials by heating to temperatures of about 200300 C. These products are more thermally stable than the original polymeric materials and show excellent solvent resistance.

The following non-limiting examples serve to illustrate the invention.

good insulating properties. The films exhibit high ultraviolet absorption and good thermal stability.

EXAMPLE II (A) Preparation of polyelectrolyte from p-phenylene dimethylene bis(diethy1 sulfonium chloride). 500 ml. of 2.0 N p-phenylene dimethylene bis(diethyl sulfonium chloride) was purged with nitrogen and chilled to 0 C. Thereafter, 500 ml. of 2.0 N sodium hydroxide was added that was prechilled to 0 C. and also purged with nitrogen. The sodium hydroxide solution was added with rapid stirring.

The reaction mixture was orange-brown at the start of the reaction, and after reacting for 15 minutes the mixture was greenish yellow. 500 ml. of 1 N HCl was added to the reaction mixture after 15 minutes reaction in order to quench the reaction. The material was so viscous that it was cut into pieces with a pair of scissors and placed in a Waring Blendor. Water (2200 ml.) was added thereto and blended until a pourable liquid resulted. The pH of the mixture was 6.

The material was dialyzed against deionized water, then run through a Waring Blendor to remove a few gel pieces. The total volume of material after dialysis was 6900 ml. This polyelectrolyte material had a normality of 0.03. The yield of polyelectrolyte was calculated to be 41 percent (207 meq.) and consisted of the following structural units H561 CgHs EXAMPLE I dried in vacuo at a temperature of 50 C. The yield was 0.57 gram (56 percent of theoretical) of a hard, yellow plastic containing 11 percent sulfur which was readily soluble in ortho-dichlorobenzene and chloroform.

Films cast from solution were hard, yellow and fluorescent. The product was identified by infrared and elemental analysis to be wherein n represents the number average degree of polymerization of the polyelectrolyte.

(B) Preparation of the phenylthio derivative of the polyelectrolyte of (A). 2 cc. of thiophenol was mixed in cc. of methanol, 20 cc. of 1 N sodium hydroxide solution having been added thereafter. This mixture was poured rapidly into 250 cc. of the polyelectrolyte material of (A) and shaken vigorously. Thereupon, a white precipitate formed immediately. The mixture was diluted to 600 cc. with methanol and held 16 hours. The precipitate was washed four times with methanol. The washings were repeated with n-pentane. The residue was then dried. The product was an off-white, hard, amorphous material which dissolved readily in benzene.

The produce was dissolved in benzene. A small amount of gel remained which was filtered off. The clear solution was freeze-dried, then dried in vacuo. The yield was S S I I 1.5 grams of a polymer composition according to the invention having the following structural units wherein the number average degree of polymerization was about 2800 and wherein a was about 9 percent, b was esconducting and adhere well to such substrates as wood, sentially zero, and c was about 91 percent of the polymer. paper, steel, aluminum and stone. Therefore, they are The number average molecular weight of the polymer useful as protective coatings.

was determined to be about 600,000 by osmometry. A The structures of the novel polymer compositions are comparison of the thoretical and actual amounts of 5 determined from nuclear magnetic resonance, infrared carbon, hydrogen, and sulfur contained in the polymer spectra, elemental analysis and osmotic pressure molecuwas made showing lar weight to be CH3 Z Theoretical: C, 79.2%; H, 5.7%; S, 15.1%. Found: wherein the number average degree of polymerizaton was C, 78.7%; H, 6.2%; S, 14.1%. approximately 700.

The polymer was nearly colorless, transparent and The properties of these novel polymeric compositions showed blue fluorescence under ultraviolet excitation. The depend on the side group Z. The glass transition temperapolymer was cast on a steel plate forming a water-retures are shown below: sistant, non-conducting, protective coating.

EXAMPLE III Side group Z Tg,* 0.

(A) Preparation of polyelectrolyte solution. To 500 a b 0 ml. of a 2.0 N solution of the monomeric salt p-phenylghenyl 61 9 73 18 ene dimethylene bis(dimethyl sulfonium chloride) was 9 61 added a mixture containing 200 ml. of benzene and 50 KZgfiififf? i; ml. of methylene chloride. The mixture was cooled to IPDQCYI 26 9 61 0 C. under an argon atmosphere. The reaction was *Measured by difierentialthermal analysis. started by adding thereto 500 ml. of a 2.0 N sodium hydroxidie solution which had been cooled to 0 C. under 8 Indicates the appioxlmate tempofatufe at which the a nitrogen atmosphere. The reaction was quenched after Polymar changes from a glassy State to a leathefy 30 minutes by adding thereto 500 ml. of 1.0 N HCl solu- 30 rubbery State- None of these P y Were Crystallinetiom Enough Water was added to the mixture to have a The temperature at which they can be molded lies slightly volume of 5000 ml. which was thereafter mixed in a above the For example the benzyl derivative can Wan-Hg Blendcm be molded to a hard, transparent yellow sheet at about The polyelectrolyte formed by the reaction had refor the y p y derivative, molding can be curring 'units of the following structure carrifid out at about H3C CH3 \69/ s -10 n=-700 This polymer was not isolated from its reaction mix- EXAMPLE IV ture but was reacted directly With various mercaptans 01 19,5 grams of 2,5-dimethy1-p-pheny1ene dimethylene thiol compounds by the procedure described bo W bis(diethy1 sulfonium chloride) was dissolved in 250 ml. produce the compositions of the inventio of deionized water. After cooling to 5 C. and flushing Preparation of p y of compositions according with nitrogen, ml. of cold 1 N sodium hydroxide to the inventioll- A merctaptide Solution was P p y solution was added with rapid stirring. After 10 minutes, dissolving the pp p mcrcaptan in a basic aqueous the mixture was diluted to 4000 ml. with ice water. The ethan l lut pr p r d y dissolving grams of mixture was dialyzed against deionized water to isolate sodium hydroxide in 100 ml. of water and diluting to 50 "th olyelectrolyte bt i d f o th lt by-produict, d 1300 ml. with absolute ethanol. The amount Of each a portion (225 percent) of this was mixed with 10 mercaptan as listed below was dissolved respectiv ly i ml. of thiophenyl dissolved in 100 ml. of tetrahydrofuran. 100 ml. of the basic aqueous ethanol. After mixing thoroughly, 25 ml. of 1 N sodium hydroxide Mercaptan: Weight, gram r solution was added rapidly. After one hour, the coagu- Thiophenol 111 50 lated polymer was recovered, lsolated, purified and dried yielding 0.92 gram of a white solid with intense blue Benzyl mercaptan 13.6 P t Buty1benZenethi01 18.3 fiuorescenceT he polyrner1c product according to the mzmaphthalenethiol VGIIiIOII WaS identified from infrared analysis and nuclear 500 ml. of the polyelectrolyte solution prepared in (A) was added rapidly to each mercaptide solution. The mixture was added rapidly to each mercaptide solution. The mixture was agitated until a lump of yellow-green gel sepa- CH rated out. I

The reaction mixtures were held at room temperature JH-CH for 24 hours. At this point, the aqueous phase was decanted, and the polymer washed free of salts with meth- H3 c=100 anol. Residual mercaptan was removed by extraction with wherein the a and b units essentially equaled zero. The acetone. The remaining solids were dispersed in dioxane. number average molecular weight of the polymer was de- A small amount 1%) of gel was removed by centrifutermined to be about 1,450,000 by osmometry. The numgation and filtration. Films were cast from the clarified ber average degree of polymerization was determined to solutions on glass plates at 50 C. The films were hard, be about 6 000. The glass transition temperature as meastransparent, yellow-green and intensely fluorescent under ured by differential thermal analysis was 58 C.

ultraviolet excitation. These films are water-resistant, non- A film was cast from a 2 percent solution of the polymer in tetrahydrofuran. The film was clear, flexible and almost colorless. It was opaque to ultraviolet light. A coating made from the above solution adhered well to wood and metal substrates and provided a clear waterthiol compound or their salts or mixtures thereof, the polyelectrolyte having recurring units of the structure resistant coating. 5 R R R R We claim: I I l l S 1. A polymer composition having recurring units of O the structure J R R r R R g Z R R R R R R l l l I l I l l R R a R R b R R 0 wherein R represents hydrogen or the methyl group, Y represents an alkyl group containing from 1 to 4 carbon atoms, Z represents an al-kyl, aryl, or ara kyl group which is stable in strongly basic solution such that the mercaptan or thiol compound from which it is derived can form a mercaptide ion except that when Z is the same as Y, b equals zero, and a, b, and 0 represent the mole percent of the structural units comprising the polymer, the sum of which equals 100 and in which a can range from O to 75 or to the point where the polymer composition remains both thermoplastic and soluble in organic solvents, b from 0 to 66.7 and c from 25 to 10-0.

2. The composition of claim 1 wherein a equals zero.

3. The composition of claim 1 wherein b equals zero.

4. The composition of claim 1 wherein both a and in equal zero.

5. The composition of claim 1 wherein Z is selected from the group consisting of phenyl, benzyl, t-butyl-phenyl, naphthyl, and C to C alkyl.

6. The composition of claim 1 which additionally has been thermally cured at a temperature from about 200 to 300 C.

7. A process for making the novel polymer compositions of claim 1 which comprises reacting in a basic solution a water-soluble polyelectrolyte with a mercaptan or wherein R represents hydrogen or the methyl group, R and R" each repreesnts an alkyl group containing from 1 to 4 carbon atoms, A represents a counterion which can be derived from any low molecular weight acid as long as it does not precipitate polymer or react with polymer in aqueous solution, and the ratio of units comprising the polyelectrolyte structure is represented by the integers and g in which the ratio of f:g ranges up to about 3:1 or to the ratio corresponding to the point of incipient water insolubility.

Reterences Cited UNITED STATES PATENTS 3,110,687 11/1963 Smith 260-214 3,342,790 9/1967 Vries 260-795 OTHER REFERENCES Houben-Weyl, Methoder der Organischen Chemie,

JOSEPH L. SCHOFER, Primary Examin r.

D. K. DENENBERG, Assistant Examiner. 

